This application claims priority based on German patent application 199 27 146.1, filed Jun. 15, 1999.
This invention relates to a position sensor for a motor vehicle, which generates, as a sensor signal, a pulse-width-modulated signal that varies as a function of position.
It is currently common practice to adjust position sensors during production or after installation of the sensors. However, mechanical adjustment of these sensors is very costly for automobile manufacturers. Therefore, for sensors installed in vehicles, it is preferable to align, calibrate, or tune, such sensors using electrical alignment techniques. This alignment could be performed within a receiver of a sensor signal and could be initiated, for example, via an existing diagnostic-interface.
However, when using electrical alignment, a reduction in an original signal range of the position sensor may occur, which leads to an undesirable reduction in a signal resolution of the sensor.
It is an object of the invention is to provide a position sensor which makes possible shifting sensor alignment into a receiver(s) to cost-effectively replace an alignment in or on the position sensor, while not negatively influencing the signal resolution ability of the position sensor.
This object and other objects of the present invention are achieved by having a position sensor for a motor vehicle, which generates a varying pulse-width-modulated, position-dependent sensor signal, with an overall measuring range of the position sensor being divided into several equal, sequential measuring ranges. The position sensor adds a fixed offset value to a digitized measurement value, with a sum of a minimum measurement value and the fixed offset value corresponding to a pulse-width-modulated signal having a minimal degree of modulation greater than 0%, and a sum of a maximum measurement value and the fixed offset value corresponding to a pulse-width-modulated signal having a maximum degree of modulation being less than 100%. Further, a sensor measurement value determined under standard conditions is stored in a nonvolatile storage of a receiver of the position sensor, as an additional offset value.